1
Water and Drought in California
Jay R. Lund
Director, Center for Watershed Sciences
Professor of Civil and Environmental Engineering
University of California, Davis
watershed.ucdavis.edu
cee.engr.ucdavis.edu/faculty/lund/
CaliforniaWaterBlog.com
Mostly dry, but many demands
2
Water use has changed California
3
AD 1873
Major Inflows to Delta (maf/month) (mean annual flows, 1 maf = 1.23 bcm)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
10 11 12 1 2 3 4 5 6 7 8 9
Sacramento River
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
1921-2003 Unimpaired
1949-1968 Historical
1986-2005 Historical
San Joaquin River
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
10 11 12 1 2 3 4 5 6 7 8 9
Sacramento River
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
1921-2003 Unimpaired
1949-1968 Historical
1986-2005 Historical
San Joaquin River
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
10 11 12 1 2 3 4 5 6 7 8 9
Sacramento River
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
1921-2003 Unimpaired
1949-1968 Historical
1986-2005 Historical
San Joaquin River
Diversions
23% 1949-1968
26% 1968-2005
Diversions
57% 1949-1968
55% 1968-2005
5
Native Habitat and Fishes Wetlands
California’s freshwater fishes
are losing
Extinct
Special Concern
Listed
OK
Salmonid
Habitat
6
State Water Project
7
Changing Problems and Reasons for Hope
1) Human water use
peaked?
2) Economy depends
less on water
abundance
3) Water markets can
shift use and
civilize change
4) We agree we have
a problem
Source: Hanak et al. 2011
8
Floods, Droughts & Lawsuits:
9
Water Rights in California – a bit 1. Riparian water rights – English Common
Law – riparian land - shared shortages
2. Appropriative water rights – “first in time,
first in right” - “use it or lose it”
3. Post-1914 Appropriative Rights – like
before, but registered with State
4. Groundwater rights – nominally correlative
with land ownership, little enforced
5. Water contracts – contract law
6. Environmental regulations – ESA, CWA, …
10
Agriculture in California
1) 400+ crops
2) $45 billion/year sales
3) Most agricultural value
of any US state
4) 4 million irrigated
hectares
5) 40 BCM water use/yr
(80% human use)
6) <4% of labor force and
state GDP
11
Agriculture in California Crop
Irrigated Crop Area
(1000 hectares)
Applied Water
(MCM)
Application
rate (m)
Alfalfa 443 7,356 1.7
Almonds, Pistachios* 416 5,174 1.2
Vine* 365 2,413 0.7
Vegetables (“truck”) 354 1,965 0.6
Corn 345 3,329 1.0
Pasture 328 4,558 1.4
Grain 288 1,649 0.6
Orchards* 270 3,314 1.2
Field (other) 270 2,407 0.9
Rice 230 3,478 1.5
Subtropical* 185 2,013 1.1
Processing Tomato 121 1,047 0.9
Cotton 111 1,117 1.0
Safflower 46 291 0.6
Cucurbits 39 259 0.7
Onion Garlic 31 305 1.0
Dry Bean 30 230 0.8
Tomato (fresh) 15 109 0.7
Potato 15 119 0.8
Sugar Beet 15 201 1.4
Grand Total 3915 41,331 1.1
Local and Statewide Activities Local Activities: - Conservation and use efficiency - Wastewater reuse - Desalination (brackish & ocean) - Groundwater use and recharge - Surface reservoir operations - Water markets and exchanges
Statewide Activities: - Inter-regional water conveyance - Surface reservoir operations - Plumbing codes & conservation incentives - Groundwater banking and recharge - Water market support and conveyance - Wastewater reuse subsidies
Integrating mix of actions – portfolio planning.
13
Sac. Valley Precipitation index
2014:
8th driest
in 106
years
14
Snowpack – Jan 26, 2015:
Trinity/ Feather/ Truckee.
Yuba-Tahoe-Merced-Walker.
San Joaquin-Kern-Owens.
15
Droughts test water systems!
1. Water systems and the societies they serve
are always changing.
2. Droughts bring attention to needs for
change
3. This drought is helping California improve
water management
4. Every generation needs at least a
threatening drought, and a threatening flood
2014 Impact Summary of Drought Impacts
16
Impact Quantity
Water supply, 2014 drought
Surface water reduction 6.6 million acre-feet
Groundwater pumping increase 5 million acre-feet
Net water shortage 1.6 million acre-feet
Statewide Economic Impacts
Crop revenue loss $810 million
Additional pumping cost $454 million
Livestock and dairy revenue loss $203 million
Total direct costs $1.5 billion
Total economic costs $2.2 billion
Total job losses 17,100
NASA Summer Idle Land Estimates Early August
17
18
Lessons for water policy • Droughts are inevitable in California
• Portfolio approach
• Groundwater
• Water markets
• Need for state agencies to work better together
• Information • Better water accounting and water use data, made
more available with better modeling
• Potential of remote sensing estimates
• Retrospective assessment of drought
Changes for Agriculture
19
1) More permanent & high value crops
2) More environmental flows
3) Tighter groundwater management
a) More wet-year recharge (field and artificial recharge)
b) More reliable wells and drought supplies
4) Nitrate groundwater contamination is inevitable
5) Some land lost to salinization and Delta flooding
6) Less landscape ET:
a) Longer fallowing rotations and more permanent fallowing
b) More habitat
7) Irrigation efficiency? Recharge vs. NO3 and salts
20
Today’s Challenges 1) Limits of traditional management
2) Major problems
– Native species and their habitats (esp. wetlands)
– Reconciling for permanent scarcity – esp. for agriculture
– Groundwater – depletion, degradation, rights
– Weak state and federal governments
3) Modernizing statewide system
– Serving many goals (conflict and mutual need)
– Rebuilding or abandoning the Delta
– Locally-driven portfolios in a statewide system
– Challenges for state government and regulation
21
Conclusions 1) Statewide water system, with local
governance and fragmented regulation
2) Limited State and Federal abilities
3) Local government is most important
4) Complexity enriches possibilities
5) Integrated portfolios are the future
6) Nature and economics
eventually prevail over
indecision and existing law
7) Droughts remind us to
change, and prepare.
22
Suggested Readings
Hanak et al. (2011) Managing
California’s Water, PPIC.org
Hanak et al. (2010) Myths of
California Water, PPIC.org
Hundley (1992), The Great
Thirst, UC Press.
Kelley (1989), Battling the Inland
Sea, UC Press.
Lund et al. (2010) Comparing
Futures for the Sacramento
San Joaquin Delta, UC Press
Pisani (1983), From Family
Farms to Agribusiness, UC Press
Mavensnotebook.com
CaliforniaWaterBlog.com
23
Will next year be dry? (from historical data, 1906-2013)
Probability next year
Sacramento Valley San Joaquin Valley
Next Year Historical Critical now Historical Critical now
Critical 0.13 0.29 0.18 0.55
Dry 0.21 0.35 0.14 0
Below Normal 0.18 0.07 0.16 0.15
C,D 0.34 0.64 0.32 0.55
C,D, BN 0.52 0.71 0.48 0.7
AN, W 0.48 0.29 0.52 0.3
24
Streamflow and El Nino (maf)
ENSO Index
An
nu
al R
un
off
, m
af
25
El Nino and drought
ENSO Index
An
nu
al R
un
off
, m
af
26
Nov.-March Runoff as Percent of Annual, Central Valley
Year
% A
nn
ual ru
no
ff in
Win
ter
y = 0.001x - 1.4657 R² = 0.0702
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1920 1940 1960 1980 2000
27
Annual Runoff of Central Valley, taf
Year
y = 87.732x - 143904 R² = 0.0216
0
10.000
20.000
30.000
40.000
50.000
60.000
70.000
80.000
1920 1940 1960 1980 2000
Resistance is Futile
28
1) Flooding in parts of the Delta
2) Reduced Delta diversions
3) Less irrigated land in the southern Central Valley
4) Less urban water use, more reuse & storm capture
5) Some native species unsustainable in the wild
6) Funding solutions mostly local and regional
7) State’s leverage is mostly regulatory, not funding
8) Nitrate groundwater contamination is inevitable
9) Groundwater will become more tightly managed
10) The Salton Sink will be largely restored
We cannot drought-proof, but we can manage better.
29
Mostly dry, but many demands Water supplies
Floods
Environmental habitat
Hydropower
Recreation
30
Water Storage Capacity and Uses in California
1. Conclusions
0
20
40
60
80
100
120
140
160
Groundwater Capacity
Surface Storage Proposed Expansions
Ca
pa
city
(m
af)
Total Capacity
Seasonal Storage
Drought Use
Water for S. Central Valley
31
1) Outflows
– Total consumptive water use (ET) about 15.3 maf/yr Mostly for 5 million acres of irrigated agriculture
– San Joaquin R. outflow average 2.7 maf/year (increasing)
2) Supplies – About 13 maf/year in local inflows (climate change?)
– About 4 maf/year of Delta imports (decreasing)
– 1-2 maf/year in groundwater overdraft (decreasing)
3) Difference – About 2 – 4 maf/year, ~ 1+ million acres
– Some acres retire due to salinity anyway
– Most retire due to water scarcity
– Likely growing profitability anyway
